The present invention relates to an induction heating apparatus which saves power by utilizing its own high frequency energy for switching operation.
Induction heating involves conversion of energy from an AC mains supply to high frequency energy and the amount of energy involved in the conversion is substantial. Use is made of a semiconductor switching device whose on-off switching operation causes a resonant circuit to oscillate at a frequency in the ultrasonic range. Due to the substantial amount of energy involved in the switching operation, the switching device needs to carry a heavy current. This creates a need for a drive circuit capable of delivering a sufficient amount of energy to the switching device and a power circuit for the drive circuit must meet such power requirement. This requirement is currently met by a large transformer and a number of capacitors of large capacitance value. Use of such components constitutes a barrier to making a compact induction heating apparatus.